The purpose of this research project is to study the effects of different growth conditions on "atypical" mycobacteria and the influence of these conditions on the free fatty acid composition of cell wall, in vitro drug immunogenicity, in vivo pathogenicity and immunogenicity. In order to systematically approach the stated goals of the study, we will use three "atypical" mycobacterium species: Mycobacterium smegmatis ATCC 607, Mycobacterium phlei F- 89 and Mycobacterium avium intracellular. These microorganisms will be grown on lipid limiting and on hydrocarbon media. The free fatty acid content of M. smegmatis, M. phlei and M. avium intracellular will be analyzed by Gas Liquid Chromatography (GLC). The drug susceptibility will be tested for each different conditionally grown "atypical" mycobacteria. Pathogenicity will be tested in mice by determining LD50 and for each different conditionally grown "atypical" mycobacteria. We will also inject conditionally grown "atypical" mycobacteria cell wall chloroform:methanol (2:1) extract into mice for immunological studies. Animals (mice) will be challenged after 5 days with Bordetella pertusis vaccine to enhance the immunological response. After final challenge injection, some of the basic immunological parameters like differential white blood cell, spleen, thymus, mesenteric lymph nodes, and bone marrow cell counts will be determined. This research will provide the information on the effects of different growth condition on the "atypical" mycobacteria and its effect on free fatty acid composition of the cell wall, drug susceptibility, pathogenicity, and immunogenicity.